Isatin derivatives for coloring keratin-containing fibers

ABSTRACT

The process of coloring keratin-containing fibers by contacting the fibers with an isatin derivative corresponding to formula (I): ##STR1## in which R 1  is a hydroxy group, an optionally C 1-4  -alkyl- or phenyl-substituted amino group, a C 3-8  alkenyl, dihydroxy-(C 3-6 )-alkyl, trihydroxy-(C 4-6 )-alkyl, tetrahydroxy-(C 5-6 )-alkyl, pentahydroxy-C 6  -alkyl, C 2-4  -aminoalkyl, C 1-4  -sulfoalkyl group, an optionally C 1-4  -alkyl-substituted 2-furylmethyl, 2-thienylmethyl, 2-pyridylmethyl, 3-pyridylmethyl, 4-pyridylmethyl group or an aralkyl group corresponding to formula (II): ##STR2## in which R 6  and R 7  independently of one another represent hydrogen, halogen atoms, hydroxy groups, amino groups optionally substituted by C 1-4  alkyl or phenyl, C 1-4  alkyl groups, C 1-4  alkoxy groups, carboxy groups or sulfo groups and R 8  is hydrogen, a C 1-4  alkyl group or a C 2-4  hydroxyalkyl group and x=0, 1 or 2, and R 2 , R 3 , R 4  and R 5  independently of one another represent hydrogen, hydroxy groups, halogen atoms, nitro groups, sulfo groups, carboxyl groups, C 1-4  alkyl groups, C 1-4  alkoxy groups or NR 9  R 10  groups, wherein R 9  and R 10  independently of one another represent hydrogen, C 1-4  alkyl groups or C 2-4  hydroxyalkyl groups, and two adjacent groups R 3 , R 4  and R 5  may represent an alkylenedioxy group containing 1 to 4 carbon atoms, and water-soluble salts thereof.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the use of certain N-substituted isatin derivatives for coloring keratin-containing fibers and to coloring formulations containing these isatin derivatives.

Keratin-containing fibers, for example hair, wool or furs, are generally colored either with substantive dyes or with oxidation dyes which are formed by oxidative coupling of one or more primary intermediates with one another or with one or more secondary intermediates. Although intensive colors with good fastness properties can be obtained with oxidation dyes, development of the color takes place under the effect of oxidizing agents, such as H₂ O₂ for example, which frequently results in damage to the fibers. Although substantive dyes are applied under more moderate conditions, their disadvantage is that the colors often have unsatisfactory fastness properties.

2. Discussion of Related Art

Coloring systems based on isatin or isatin derivatives offer an alternative solution. Isatin is described in DE-OS 36 35 147 A1 as a substantive dye for coloring keratin fibers either on its own or in conjunction with quinone dyes. Unfortunately, the range of variation of the color tones obtainable is limited. In most cases, a golden color is obtained.

Another isatin-containing coloring system is described in EP 359 465 A2. In this case, the color is obtained with a ketimine (Schiff's base) produced by the reaction of an isatin with an aniline derivative. The ketimine is either applied as such to keratin fibers where it develops color or, alternatively, a mixture consisting of an isatin and an aniline derivative is applied to the fibers and initially forms the ketimine in situ, after which the color develops on the fibers.

EP 497 697 A1 describes hair coloring formulations based on isatins and aminoindoles or indolines containing a primary amino group, Schiff's bases being formed in a condensation reaction.

EP 0 502 783 A1 describes hair coloring formulations containing isatins and aminopyridines or isatins and aminopyrimidines containing a primary amino group.

EP 0 502 784 A1 describes hair coloring formulations containing isatins and substituted diamines or aminophenols or isatins and (bisaryl) alkylenediamines.

Unfortunately, the hair colors obtainable with these isatins are not always satisfactory in regard to the brilliance and intensity of the color tones.

The problem addressed by the present invention was to provide hair coloring systems based on isatins which would give particularly intensive colors. It has now surprisingly been found that certain N-substituted isatin derivatives are outstanding in satisfying these requirements and are eminently suitable for coloring keratin fibers.

Examples of keratin-containing fibers are wool, furs, skins and human hair. In principle, however, the N-substituted isatin derivatives described in more detail hereinafter may also be used for coloring other natural fibers, for example cotton, jute, sisal, linen or silk, modified natural fibers, for example regenerated cellulose, nitrocellulose, alkyl or hydroxyalkylcellulose or acetyl cellulose and synthetic fibers, for example polyamide, polyacrylonitrile, polyurethane and polyester fibers.

DESCRIPTION OF THE INVENTION

The present invention relates to the use of isatin derivatives corresponding to formula I: ##STR3## in which R¹ is a hydroxy group, an optionally C₁₋₄ alkyl- or phenyl-substituted amino group, a C₃₋₈ alkenyl, dihydroxy-(C₃₋₆)-alkyl, trihydroxy-(C₄₋₆)-alkyl, tetrahydroxy-(C₅₋₆)-alkyl, pentahydroxy-C₆ -alkyl, C₂₋₄ -aminoalkyl, C₁₋₄ -sulfoalkyl group, an optionally C₁₋₄ -alkyl-substituted 2-furylmethyl, 2-thienylmethyl, 2-pyridylmethyl, 3-pyridylmethyl, 4-pyridylmethyl group or an aralkyl group corresponding to formula (II): ##STR4## in which R⁶ and R⁷ independently of one another represent hydrogens, halogen atoms, hydroxy groups, amino groups optionally substituted by C₁₋₄ alkyl or phenyl, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, carboxy groups or sulfo groups and R⁸ is hydrogen, a C₁₋₄ alkyl group or a C₂₋₄ hydroxyalkyl group and x=0, 1 or 2,

and R², R³, R⁴ and R⁵ independently of one another represent hydrogens, hydroxy groups, halogen atoms, nitro groups, sulfo groups, carboxyl groups, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups or NR⁹ R¹⁰ groups, where R⁹ and R¹⁰ independently of one another represent hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups, and two adjacent groups R³, R⁴ and R⁵ may even represent an alkylenedioxy group containing 1 to 4 carbon atoms, and water-soluble salts thereof for coloring keratin-containing fibers.

Examples of water-soluble salts are inter alia the alkali metal or ammonium salts of acidic isatins corresponding to formula I and the hydrochlorides, hydrobromides or hydrogen sulfates of basic isatins corresponding to formula 1.

The isatins corresponding to formula I are either compounds known from the literature or may be prepared by standard syntheses known from the literature, inter alia by reaction of isatin or isatin derivatives substituted in the benzene nucleus or sodium salts thereof with corresponding halogen or epoxy compounds. Examples of isatins corresponding to formula I are N-(2,3-dihydroxypropyl)-, N-(2-sulfoethyl)-, (3-sulfopropyl)-, N-allyl-, N-(2-dimethylamino)-, N-(2-pyrrolidino)-, N-(2-piperidino)-, (2-morpholinoethyl)-, N-(2-furylmethyl)-, N-(2-thienylmethyl)-, N-(2-, N-(3- or N-(4-pyridylmethyl)-isatin, N-allyl isatin-5-sulfonic acid, 5-chloro-, 5-methyl-N-(hydroxyethyl)-isatin, 5,7-dichloro-, 5-nitro-N-allyl isatin and the alkali metal salts of the acidic compounds.

Isatin derivatives corresponding to formula 1, in which R¹ is an allyl group, a hydroxy group or a 2-sulfoethyl or 2-sulfopropyl group and R² to R⁵ are hydrogens are preferably used for coloring keratin-containing fibers.

The isatin derivatives corresponding to formula I give yellow color tones. Particularly brilliant colors in the yellow, red and violet and black ranges with good fastness properties (fastness to light, washing and rubbing) are obtained when the isatin derivatives corresponding to formula I are used together with aminofunctional compounds, for example primary aliphatic amines containing at least one additional amino or C₁₋₄ alkoxy group in the C chain, aromatic di- and trihydroxy compounds, for example pyrogallol, hydroxyhydroquinone, phloroglucinol, resorcinol, 2-, 4-methyl resorcinol, 3-dimethylaminophenol, or together with heterocyclic aromatic compounds.

Particularly suitable aminofunctional compounds are amino acids and oligopeptides. Accordingly, the present invention also relates to formulations for coloring keratin-containing fibers containing at least one isatin derivative corresponding to formula I and at least one amino acid or an oligopeptide made up of 2 to 9 amino acids.

Suitable amino acids are any naturally occurring and synthetic amino acids, for example the amino acids obtainable by hydrolysis from vegetable or animal proteins, for example collagen, keratin, casein, elastin, soya protein, wheat gluten or almond protein. Both amino acids showing an acidic reaction and those showing an alkaline reaction may be used.

Suitable oligopeptides are any oligopeptides produced from naturally occurring and synthetic amino acids. The oligopeptides may be naturally occurring or synthetic oligopeptides and also the oligopeptides present in polypeptide or protein hydrolyzates providing they are sufficiently soluble in water for use in the coloring formulations according to the invention. Examples are glutathione and the oligopeptides present in the hydrolyzates of collagen, keratin, casein, elastin, soya protein, wheat gluten or almond protein.

However, amino acids or oligopeptides selected from the group consisting of arginine, cysteine, methionine, proline, tyrosine, valine, glycine, glutamic acid, histidine, aspartic acid, alanine, tryptophan, cystine, lysine, hydroxyproline, leucine, isoleucine, phenyl alanine, 3,4-dihydroxyphenyl alanine, serine, ornithine, threonine, glutathione are particularly suitable for use in the coloring formulations according to the invention.

The present invention also relates to formulations for coloring keratin-containing fibers containing at least one isatin derivative corresponding to formula I and at least one aromatic amine corresponding to formula III: ##STR5## in which R¹¹, R¹² and R¹³ are hydrogens, C₁₋₄ alkyl groups, C₁ 4 alkoxy groups, hydroxy groups, C₂₋₄ hydroxyalkyl groups, carboxyl groups, sulfo groups, C₁₋₄ aminoalkyl groups or NR¹⁴ R¹⁵ groups, where R¹⁴ and R¹⁵ independently of one another are hydrogens, C₁₋₄ alkyl groups, aryl groups or C₂₋₄ hydroxyalkyl groups; two of the groups R¹¹, R¹² and R¹³ together may also form a fused benzene ring optionally substituted by C₁₋₄ alkyl, hydroxy, carboxyl, sulfo, C₁₋₄ aminoalkyl or amino.

Examples are p-phenylenediamine, 3-amino-6-methylphenol, o-phenylenediamine, sulfanilic acid, 1,5-, 1,8-, 2,3-diaminonaphthalene, 6-amino-1-naphthol-3-sulfonic acid, 4-amino-, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenylamine-2-sulfonic acid, 4-aminodiphenylamine, N,N'-bis-(2-hydroxyethyl)-p-phenylenediamine, 4-dimethylanilinoaniline.

Preferred coloring formulations are those in which the aromatic amine of formula III is selected from the group consisting of p-tolylenediamine, 4-aminophenol, 4-amino-2-aminomethylphenol, 3,4-diaminobenzoic acid, 1-(β-hydroxyethyl)-2, 5-diaminobenzene.

The present invention also relates to formulations for coloring keratin-containing fibers containing at least one isatin derivative corresponding to formula I and at least one aromatic amine corresponding to formula IV: ##STR6## in which Y is a direct bond or a group CO, SO, O, S, NR²⁰, where R²⁰ is hydrogen, C₁₋₄ alkyl or C₂₋₄ hydroxyalkyl, or O-(CH₂ -Z-CH₂ -O)_(m), where Z is a direct bond, a group CH₂, CHOH or CH₂ OC₂ H₄ OCH₂ and m is an integer of 1 to 4, or Y may even be a saturated or unsaturated alkylene group containing 1 to 4 carbon atoms which may optionally be substituted by OH and R¹⁶, R¹⁷, R¹⁸ and R¹⁹ are hydrogens, C₁₋₄ alkyl groups, C₂₋₄ hydroxyalkyl groups, C₂₋₄ -(C₁₋₄ -alkoxy)-alkyl groups or groups NR²¹ PR²² or OR²³, where R²¹, R²² and R²³ independently of one another represent hydrogens, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, C₂₋₄ hydroxyalkyl groups or C₂₋₄ -(C₁₋₄ -alkoxy)-alkyl groups, with the proviso that at least one of the groups R¹⁶ and R¹⁷ and one of the groups R¹⁸ and R¹⁹ is a group NR²¹ R²² or OR²³.

Coloring formulations in which the aromatic amine of formula III is 1,3-bis-(2,4-diaminophenoxy)-propane, 1,8-bis-(2,5-diaminophenoxy)-3,6-dioxaoctane or 4,4'-diaminodiphenylamine are preferred.

The present invention also relates to formulations for coloring keratin-containing fibers containing at least one isatin derivative corresponding to formula I and at least one aminopyrimidine corresponding to formula V: ##STR7## in which R²⁴, R²⁵, R²⁶, R²⁷, R²⁸ and R²⁹ independently of one another are hydrogens, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups and Z is hydrogen, an OH group or an NR³⁰ R³¹ group, where R³⁰ and R³¹ independently of one another are hydrogens, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups.

Preferred coloring formulations are those in which unsubstituted 2,4,5,6-tetraaminopyrimidine is used.

Other substances which may be used together with isatin derivatives corresponding to formula I are heterocycles, for example pyrrole, 2,5-dimethyl-3-ethyl pyrrole, 2-, 3-, 4-amino-, 2-amino-3-hydroxy-, 2,6-diamino-, 2,5-diamino-, 2,3-diamino-, 2-dimethylamino-5-amino-, 3-amino-2-methylamino-6-methoxy-, 2,3-diamino-6-methoxy-, 2,4,5-triamino-, 2,6-dihydroxy-3,4-dimethyl pyridine, 4,5,6-triamino-, 4-hydroxy-2,5,6-triamino-, 2,4,5,6-tetraamino-, 2-methylamino-4,5,6-triamino-, 2,4-, 4,5-diamino-, 2-amino-4-methoxy-6-methyl pyrimidine, 3,5-diaminopyrazole, -1,2,4-triazole, 3-amino-, 3-amino-5-hydroxypyrazole, 2-, 3-, 8-aminoquinoline, 4-aminoquinaldine, 2-, 6-aminonicotinic acid, 5-aminoisoquinoline, 4-, 5-, 6-, 7-aminoindole, 5-, 6-aminoindazole, 5-, 7-aminobenzimidazole, -benzothiazole. Indole and indoline derivatives are particularly suitable.

The present invention also relates to formulations for coloring keratin-containing fibers containing at least one isatin derivative corresponding to formula I and

at least one indole derivative corresponding to formula VIa: ##STR8## in which R³² is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³³ is hydrogen or a carboxyl group and R³⁴, R³⁵ and R³⁶ are hydrogens, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups, or

at least one indoline derivative corresponding to formula VIb: ##STR9## in which R³⁷ is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³⁸ is hydrogen or a carboxyl group and R³⁹, R⁴⁰ and R⁴¹ are hydrogens, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups.

Preferred coloring formulations are those in which the indole derivative corresponding to formula VIa or the indoline derivative corresponding to formula VIb is selected from the group consisting of 5,6-dihydroxyindole, 5,6-diacetoxyindole, 4-hydroxyindoline, 6-aminoindoline and 5,6-dihydroxyindoline.

Several different isatin derivatives corresponding to formula I may also be used together in the coloring formulations according to the invention. Several different amino acids or oligopeptides and several different compounds corresponding to formulae II, IV, V, VIa and VIb may also be used together.

The coloring formulations according to the invention give intensive colors at physiologically tolerable temperatures of below 45° C. Accordingly, they are particularly suitable for coloring human hair.

For application to human hair, the coloring formulations according to the invention may be incorporated in a water-containing cosmetic carrier. Suitable water-containing cosmetic carriers are, for example, creams, emulsions, gels or even surfactant-containing foaming solutions, such as shampoos for example, or other preparations which are suitable for application to the hair. The isatins corresponding to formula I and also the amino acids and oligopeptides or the compounds corresponding to formulae III, IV, V, VIa and VIb are each present in quantities of 0.01 to 20% by weight and preferably 1 to 7% by weight, based on the coloring preparation as a whole.

The water-containing cosmetic carrier typically contains wetting agents and emulsifiers, such as anionic, nonionic or ampholytic surfactants, for example fatty alcohol sulfates, alkane sulfonates, α-olefin sulfonates, fatty alcohol polyglycol ether sulfates, alkyl glycosides, ethylene oxide adducts with fatty alcohols, with fatty acids, with alkylphenols, with sorbitan fatty acid esters, with fatty acid partial glycerides and fatty acid alkanolamides; thickeners, for example fatty alcohols, fatty acids, paraffin oils, fatty acid esters and other fatty components in emulsified form; water-soluble polymeric thickeners, such as natural gums, for example gum arabic, karaya gum, guar gum, carob bean flour, linseed gums and pectin, biosynthetic gums, for example xanthan gum and dextrans, synthetic gums, for example agar agar and algin, starch fractions and derivatives, such as amylose, amylopectin and dextrins, modified cellulose molecules, for example methyl cellulose, hydroxyalkyl cellulose and carboxymethyl cellulose, clays, for example bentonite, or fully synthetic hydrocolloids, for example polyvinyl alcohol or polyvinyl pyrrolidone, hair-care additives, for example water-soluble cationic polymers, anionic polymers, nonionic polymers, amphoteric or zwitterionic polymers, pantothenic acid, vitamins, plant extracts or cholesterol, pH regulators, complexing agents and perfume oils and also reducing agents for stabilizing the ingredients, for example ascorbic acid. Finally, dyes may also be present to color the cosmetic preparations.

The pH value of the ready-to-use coloring preparations is between 2 and 11 and preferably between 5 and 9. Where components oxidizable in air, for example 5,6-dihydroxyindole, 5,6-dihydroxyindoline and derivatives thereof, are used, a mildly alkaline pH value of 7 to 11 and preferably 8 to 10 is of advantage.

To color hair, the coloring formulations according to the invention are applied to the hair in the form of the water-containing cosmetic carrier in a quantity of 100 g, left thereon for around 30 minutes and then rinsed out or washed out with a commercial shampoo.

If the coloring formulations according to the invention are used in the form of a water-containing cosmetic preparation, it is of advantage (but not always necessary) to package the isatin derivative corresponding to formula I separately from the second reactive component, i.e. the amino acid or the oligopeptide or the compounds corresponding to formulae III, IV, V, VIa and VIb.

The two components (isatin derivative of formula I and the second reactive component) may then be applied to the hair either at the same time or even successively. It does not matter which of the two components is applied first. Application of the first component and application of the second component may be separated by a time interval of up to 30 minutes.

However, it is of particular advantage to package all the components together in a water-free powder-form preparation.

Accordingly, the present invention also relates to hair coloring formulations in the form of a powder containing at least one isatin derivative corresponding to formula I in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight and an amino acid or an oligopeptide made up of 2 to 9 amino acids in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight, based on the powder-form coloring formulation as a whole.

Particularly preferred hair coloring formulations are those in which the isatin derivative corresponding to formula I is selected from N-allyl isatin, N-hydroxy isatin and N-(2-sulfoethyl)-isatin and the amino acid or the oligopeptide is selected from arginine, cysteine, methionine, proline, tyrosine, valine, glycine, glutamic acid, histidine, aspartic acid, alanine, tryptophan, cystine, lysine, hydroxyproline, leucine, isoleucine, phenyl alanine, 3,4-dihydroxyphenyl alanine, serine, ornithine, threonine and glutathione.

The present invention also relates to hair coloring formulations in the form of a powder containing at least one isatin derivative corresponding to formula I in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight and at least one aromatic amine corresponding to formula III in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight, based on the powder-form coloring formulation as a whole.

Particularly preferred hair coloring formulations are those in which the isatin derivative corresponding to formula I is selected from N-allyl isatin, N-hydroxyisatin, N-(2-sulfoethyl)-isatin and N-(2-sulfopropyl)-isatin and the hydroxyisatin, N-(2-sulfoethyl)-isatin and N-(2-sulfopropyl)-isatin and the aromatic amine corresponding to formula III is selected from the group consisting of p-tolylenediamine, 4-aminophenol, 4-amino-2-aminomethylphenol, 3,4-diaminobenzoic acid, 1-(β-hydroxyethyl)-2,5-diaminobenzene.

The present invention also relates to hair coloring formulations in the form of a powder containing at least one isatin derivative corresponding to formula I in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight and at least one aromatic amine corresponding to formula IV in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight, based on the powder-form coloring formulation as a whole.

Particularly preferred hair coloring formulations are those in which the isatin derivative corresponding to formula I is selected from N-allyl isatin, N-hydroxy isatin, N-(2-sulfoethyl)-isatin and N-(2-sulfopropyl)-isatin and the aromatic amine corresponding to formula IV is 1,3-bis-(2,4-diaminophenoxy)propane.

The present invention also relates to hair coloring formulations in the form of a powder containing at least one isatin derivative corresponding to formula I in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight and at least one aminopyrimidine corresponding to formula V in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight, based on the powder-form coloring formulation as a whole.

Particularly preferred hair coloring formulations are those in which the isatin derivative corresponding to formula I is selected from N-allyl isatin, N-hydroxyisatin, N-(2-sulfoethyl)-isatin and N-(2-sulfopropyl)-isatin and the aminopyrimidine corresponding to formula V is unsubstituted tetraaminopyrimidine.

The present invention also relates to hair coloring formulations in the form of a powder containing at least one isatin derivative corresponding to formula I in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight and at least one indole derivative corresponding to formula VIa or an indoline derivative corresponding to formula VIb in a quantity of 1 to 90% by weight and preferably 20 to 50% by weight, based on the powder-form coloring formulation as a whole.

Particularly preferred hair coloring formulations are those in which the isatin derivative corresponding to formula I is selected from N-allyl isatin, N-hydroxy isatin, N-(2-sulfoethyl)-isatin and N-(2-sulfopropyl)-isatin and the indole derivative corresponding to formula Via and the indoline derivative corresponding to formula VIb are selected from 5,6-dihydroxyindole, 5,6-diacetoxyindole, 4-hydroxyindoline, 6-aminoindoline and 5,6-dihydroxyindoline.

The isatins corresponding to formula I may also advantageously be combined with pyridines such as, for example, 2,6-dihydroxy-3,4-dimethylpyridine, 2-amino-3-hydroxypyridine, ² -methylamino-3-amino-6-methoxypyridine, 3,5-diamino-2,6-dimethoxypyridine as a second component.

In the most simple case, the powder-form hair coloring formulations contain only a water-soluble polymeric thickener besides the two reactive components (isatin derivative corresponding to formula I and amino acid or oligopeptide or compounds corresponding to formulae III, IV, V, VIa and VIb). The function of the thickener is to provide the ready-to-use hair coloring preparation obtained after the addition of water with the consistency required for application. Suitable thickeners are, for example, natural gums, for example guar flour, gum arabic, karaya gum, carob bean flour, linseed gums and pectin, biosynthetic gums, such as for example xanthan gum and dextrans, synthetic gums, for example agar agar and algin, starch fractions and derivatives, such as amylose, amylopectin and dextrins, modified cellulose molecules, for example methyl cellulose, hydroxyalkyl cellulose and carboxymethyl cellulose.

Other optional components in the powder-form hair coloring formulations are metal salts, for example the acetates, sulfates, chlorides, bromides, carbonates, glycolates, lactates or gluconates of the alkali and alkaline earth metals and of zinc and manganese(l I), surfactants, for example anionic, nonionic, amphoteric or zwitterionic or cationic surfactants, hair-care additives, for example water-soluble cationic polymers, anionic polymers, amphoteric or zwitterionic polymers, pantothenic acid, vitamins, plant extracts, complexing agents, perfume components and also reducing agents, for example ascorbic acid.

To prepare the ready-to-use hair coloring preparation, 1 to 30 g and preferably 3 to 15 g of the powder are made up to 100 g with hot water (90° to 100° C.). Water/alcohol mixtures or other cosmetically compatible solvents may also be used to dissolve the powder. Individual components of the mixture may even be separately dry-blended and stored.

After cooling to around 40° C., the ready-to-use hair coloring preparation is applied to the hair and left thereon for 30 minutes. The hair is then rinsed or washed with a commercial hair shampoo.

In one particular method of coloring, the components are heated to boiling point in water and allowed to react with one another, the reaction mixture is cooled and the deposit is filtered off and then dispersed in water for use as a substantive dye for coloring hair.

The following Examples are intended to illustrate the invention without limiting it in any way.

EXAMPLES

A suspension of 10 mmoles of an isatin corresponding to formula I and 10 mmoles of a second component in 100 ml of water was prepared. The suspension was heated to boiling temperature and filtered after cooling. The pH value was then adjusted to 6. Strands of 90% grey, but non-pretreated human hair were then placed in this coloring solution for 30 minutes at 30° C. The particular coloring temperatures, coloring times, color tones and depths of color are shown in Tables 1 to 3.

Depth of color was evaluated on the following scale:

-: Very pale color, if any

(+): Weak intensity

+: Medium intensity

+(+): Medium to strong intensity

++Strong intensity

++(+): Strong to very strong intensity

+++: Very strong intensity

                  TABLE 1                                                          ______________________________________                                         Coloring with N-allyl isatin                                                                                    Depth                                                                          of                                            Second component     Color tone  color                                         ______________________________________                                         --                   Pale yellow (+)                                           2,5-Diaminotoluene H.sub.2 SO.sub.4                                                                 Red-brown   ++(+)                                         2,4,5,6-Tetraaminopyrimidine H.sub.2 SO.sub.4                                                       Dark orange ++(+)                                         3,4-Diaminobenzoic acid                                                                             Light brown-                                                                               +                                                                  orange                                                    2-(2,5-Diaminophenyl)-ethanol H.sub.2 SO.sub.4                                                      Brown-red   ++(+)                                         1,8-Bis-(2,5-diaminophenoxy)-3,6-                                                                   Dark grey   ++(+)                                         dioxaoctane 4HCl                                                               2-Aminomethyl-3-amino-6-methoxy-                                                                    Dark yellow-grey                                                                           ++(+)                                         pyrimidine 2HCl                                                                2-Aminomethyl-4-aminophenol 2HCl                                                                    Orange      ++                                            1,3-Bis-(2,4-diaminophenoxy)-propane 4HCl                                                           Beige-grey  +                                             4-(4-Amino-n-toluidino)-phenol                                                                      Light grey-violet                                                                          (+)                                           N,N-Dimethyl-p-phenylenediamine H.sub.2 SO.sub.4                                                    Dark violet +++                                           N-Phenyl-p-phenylenediamine HCl                                                                     Light brown +(+)                                          4,4'-Diaminodephenylamine H.sub.2 SO.sub.4                                                          Dark violet-blue                                                                           +++                                           N-(4-Methoxyphenyl)-p-phenylene-                                                                    Light brown +(+)                                          diamine HCl                                                                    4,4'-Diaminodiphenylamine-2-sulfonic acid                                                           Violet red  +++                                           2,4-Dimethyl-3-ethyl pyrrole                                                                        Yellow      +                                             1-(o-Aminophenyl)-pyrrole                                                                           Yellow      +(+)                                          N-methyl pyrrole     Yellow      +(+)                                          L-Histidine          Olive yellow                                                                               +                                             L-Arginine           Pink        +                                             L-Tryptophan         Pale yellow (+)                                           Pyrrole              Olive yellow                                                                               (+)                                           L-Ornithine HCl      Pale yellow (+)                                           2,6-Dimethoxy-3,5-diaminopyridine HCl                                                               Green-black +++                                           ______________________________________                                    

                  TABLE 2                                                          ______________________________________                                         Coloring with N-hydroxyisatin                                                                                 Depth of                                        Second component    Color tone color                                           ______________________________________                                         --                  Pale yellow                                                                               (+)                                             p-Tolylenediamine H.sub.2 SO.sub.4                                                                 Copper     ++                                              Tetraaminopyrimidine H.sub.2 SO.sub.4                                                              Orange-copper                                                                             ++                                              2-(2,5-Diaminophenyl)-ethanol H.sub.2 SO.sub.4                                                     Copper     ++                                              1,8-Bis-(2,5-diaminophenoxy-3,6-dioxa-                                                             Violet-brown                                                                              ++                                              octane 4HCl                                                                    ______________________________________                                    

                  TABLE 3                                                          ______________________________________                                         Coloring with N-(2-sulfoethyl)-isatin                                                                          Depth of                                       Second component     Color tone color                                          ______________________________________                                         --                   Yellow     +                                              2,5-Diaminotoluene H.sub.2 SO.sub.4                                                                 Violet-red ++(+)                                          2,4,5,6-Tetraaminopyrimidine H.sub.2 SO.sub.4                                                       Dark copper                                                                               ++                                             3,4-Diaminobenzoic acid                                                                             Yellow-beige                                                                              (+)                                            2-(2,5-Diaminophenyl)-ethanol H.sub.2 SO.sub.4                                                      Copper     ++                                             1,8-Bis-(2,5-diaminophenoxy)-3,6-dioxa-                                                             Dark grey  ++                                             octane 4HCl                                                                    2-Methylamino-3-amino-6-methoxy-                                                                    Pale violet                                                                               (+)                                            pyridine 2HCl                                                                  2-Aminomethyl-4-aminophenol 2HCl                                                                    Deep yellow                                                                               ++                                             1,3-Bis-(2,4-diaminophenoxy)-propane 4HCl                                                           Olive-grey +                                              N,N-Dimethyl-p-phenylenediamine H.sub.2 SO.sub.4                                                    Red-violet ++(+)                                          4,4-Diaminodiphenylamine H.sub.2 SO.sub.4                                                           Dark blue-grey                                                                            ++(+)                                          4,4-Diaminodiphenylamine-2-sulfonic acid                                                            Light violet-red                                                                          +(+)                                           2,4-Dimethyl-3-ethyl pyrrole                                                                        Yellow-brown                                                                              ++                                             L-Tryptophan         Brown-yellow                                                                              +                                              L-Tyrosine           Yellow     +                                              Pyrrole              Pale                                                      2,6-Dimethoxy-3,5-diaminopyridine                                                                   Green-black                                                                               +++                                            ______________________________________                                     

What is claimed is:
 1. The process of coloring keratin-containing fibers comprising contacting said fibers with an isatin derivative corresponding to formula (I): ##STR10## in which R¹ is a hydroxy group, an optionally C₁₋₄ -alkyl- or phenyl-substituted amino group, a C₃₋₈ alkenyl, dihydroxy-(C₃₋₆)-alkyl, trihydroxy-(C₄₋₆)-alkyl, tetrahydroxy-(C₅₋₆)-alkyl, pentahydroxy-C₆ -alkyl, C₂₋₄ -aminoalkyl, C₁₋₄ -sulfoalkyl group, an optionally C₁₋₄ -alkyl-substituted 2-furylmethyl, 2-thienylmethyl, 2-pyridylmethyl, 3-pyridylmethyl, 4-pyridylmethyl group or an aralkyl group corresponding to formula (II): ##STR11## in which R⁶ and R⁷ independently of one another represent hydrogen, halogen atoms, hydroxy groups, amino groups optionally substituted by C₁₋₄ alkyl or phenyl, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, carboxy groups or sulfo groups and R⁸ is hydrogen, a C₁₋₄ alkyl group or a C₂₋₄ hydroxyalkyl group and x=0, 1 or 2,and R², R³, R⁴ and R⁵ independently of one another represent hydrogen, hydroxy groups, halogen atoms, nitro groups, sulfo groups, carboxyl groups, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups or NR⁹ R¹⁰ groups, wherein R⁹ and R¹⁰ independently of one another represent hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups, and two adjacent groups R³, R⁴ and R⁵ may represent an alkylenedioxy group containing 1 to 4 carbon atoms, and water-soluble salts thereof.
 2. A process as in claim 1 wherein R¹ is an allyl group, a hydroxy group or a 2-sulfoethyl or 2-sulfopropyl group and R² to R⁵ are hydrogen.
 3. A process as in claim 1 including contacting said fibers with at least one amino acid or an oligopeptide containing 2 to 9 amino acids.
 4. A process as in claim 3, wherein said amino acid or said oligopeptide is selected from the group consisting of arginine, cysteine, methionine, proline, tyrosine, valine, glycine, glutamic acid, histidine, aspartic acid, alanine, tryptophan, cystine, lysine, hydroxyproline, leucine, isoleucine, phenyl alanine, 3,4-dihydroxyphenyl alanine, serine, ornithine, threonine and glutathione.
 5. A process as in claim 1 including contacting said fibers with at least one aromatic amine corresponding to formula (III): ##STR12## in which R¹¹, R¹² and R¹³ are hydrogen, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, hydroxy groups, C₂₋₄ hydroxyalkyl groups, carboxyl groups, sulfo groups, C₁₋₄ aminoalkyl groups or NR⁴ R¹⁵ groups, wherein R¹⁴ and R¹⁵ independently of one another are hydrogen, C₁₋₄ alkyl groups, aryl groups or C₂₋₄ hydroxyalkyl groups; two of the groups R¹¹, R¹² and R¹³ together may form a fused benzene ring optionally substituted by a C₁₋₄ alkyl, hydroxy, carboxyl, sulfo, C₁₋₄ aminoalkyl or amino group.
 6. A process as in claim 5 wherein said aromatic amine corresponding to formula (III) is selected from the group consisting of p-tolylenediamine, 4-aminophenol, 4-amino-2-aminomethylphenol, 3,4-diaminobenzoic acid, and 1-(β-hydroxyethyl)-2,5-diaminobenzene.
 7. A process as in claim 1 including contacting said fibers with at least one aromatic amine corresponding to formula (IV): ##STR13## in which Y is a direct bond or a group CO, SO, O, S, NR²⁰, wherein R²⁰ is hydrogen, C₁₋₄ alkyl or C₂₋₄ hydroxyalkyl, or O-(CH₂ -Z-CH₂ -O)_(m), wherein Z is a direct bond, a group CH₂, CHOH or CH₂ OC₂ H₄ OCH₂ and m is an integer of 1 to 4, or Y is a saturated or unsaturated alkylene group containing 1 to 4 carbon atoms which is optionally substituted by OH and R¹⁶, R¹⁷, R¹⁸ and R¹⁹ are hydrogen, C14 alkyl groups, C24 hydroxyalkyl groups, C₂₋₄ -(C₁₋₄ -alkoxy)-alkyl groups or groups NR²¹ R²² or OR²³, wherein R²¹, R²² and R²³ independently of one another represent hydrogen, C₁₋₄ alkyl groups, C₂₋₄ C₁₋₄ alkoxy groups, C₂₋₄ hydroxyalkyl groups or C₂₋₄ -(C₁₋₄ -alkoxy)-alkyl groups, with the proviso that at least one of the groups R¹⁶ and R¹⁷ and one of the groups R¹⁸ and R¹⁹ is a group NR²¹ R₂₂ or OR²³.
 8. A process as in claim 7 wherein said aromatic amine corresponding to formula (IV) is selected from 1,3-bis-(2,4-diaminophenoxy)-propane, 1,8-bis-(2,5-diaminophenoxy)-3,6-dioxaoctane and 4,4'-diaminodiphenylamine.
 9. A process as in claim 1 including contacting said fibers with at least one aminopyrimidine corresponding to formula (V): ##STR14## in which R²⁴, R²⁵, R²⁶, R²⁷, R²⁸ and R²⁹ independently of one another are hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups and Z is hydrogen, an OH group or an NR³⁰ R³¹ group, wherein R³⁰ and R³¹ independently of one another are hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups.
 10. A process as in claim 9 wherein the substituents R²⁴ to R²⁹ in tetraaminopyrimidine corresponding to formula (V) are hydrogens.
 11. A process as in claim 1 including contacting said fibers with at least one indole derivative corresponding to formula (VIa): ##STR15## in which R³² is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³³ is hydrogen or a carboxyl group and R³⁴, R³⁵ and R³⁶ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups, or at least one indoline derivative corresponding to formula (VIb): ##STR16## in which R³⁷ is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³⁸ is hydrogen or a carboxyl group and R³⁹, R⁴⁰ and R⁴¹ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups.
 12. A process as in claim 11 wherein said indole derivative corresponding to formula (VIa) or said indoline derivative corresponding to formula (VIb) is selected from the group consisting of 5,6-dihydroxyindole, 5,6-diacetoxyindole, 4-hydroxyindoline, 6-aminoindoline and 5,6-dihydroxyindoline.
 13. A hair coloring composition comprising an isatin derivative corresponding to formula (I): ##STR17## in which R¹ is a hydroxy group, an optionally C₁₋₄ -alkyl- or phenyl-substituted amino group, a C₃₋₈ alkenyl, dihydroxy-(C₃₋₆)-alkyl, trihydroxy-(C₄₋₆)-alkyl, tetrahydroxy-(C₅₋₆)-alkyl, pentahydroxy-C₆ -alkyl, C₂₋₄ -aminoalkyl, C₁₋₄ -sulfoalkyl group, an optionally C₁₋₄ -alkyl-substituted 2-furylmethyl, 2-thienylmethyl, 2-pyridylmethyl, 3-pyridylmethyl, 4-pyridylmethyl group or an aralkyl group corresponding to formula (II): ##STR18## in which R⁶ and R⁷ independently of one another represent hydrogen, halogen atoms, hydroxy groups, amino groups optionally substituted by C₁₋₄ alkyl or phenyl, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, carboxy groups or sulfo groups and R² is hydrogen, a C₁₋₄ alkyl group or a C₂₋₄ hydroxyalkyl group and x=0, 1 or 2, and R², R³, R⁴ and R⁵ independently of one another represent hydrogen, hydroxy groups, halogen atoms, nitro groups, sulfo groups, carboxyl groups, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups or NR⁹ R¹⁰ groups, wherein R⁹ and R¹⁰ independently of one another represent hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups, and two adjacent groups R³, R⁴ and R⁵ may represent an alkylenedioxy group containing 1 to 4 carbon atoms, and water-soluble salts thereof; and an aminofunctional compound selected from the group consisting of (a) an amino acid or an oligopeptide containing 2 to 9 amino acids, (b) an aromatic amine corresponding to formula (III): ##STR19## in which R¹¹, R¹², and R¹³ are hydrogen C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, hydroxy groups, C₂₋₄ hydrogen groups, carboxyl groups, sulfo groups, C₁₋₄ aminoalkyl groups or NR¹⁴ R¹⁵ groups, wherein R¹⁴ and R¹⁵ independently of one another are hydrogen. C₁₋₄ alkyl groups, aryl groups or C₂₋₄, hydroxyalkyl groups, two of the groups R¹¹, R¹² and R¹³ together may form a fused benzene ring optionally substituted by a C₁₋₄ alkyl hydroxy, carboxyl, sulfo, C₁₋₄ aminoalkyl or amino group, (c) an aromatic amine corresponding to formula (IV): ##STR20## in which Y is a direct bond or a group CO, SO, O, S, NR²⁰, wherein R²⁰ is hydrogen, C₁₋₄ alkyl or 2-4 hydroxyalkyl, or O-(CH₂ -Z-CH₂ -O)_(m), wherein Z is a direct bond, a group CH₂ or CHOH or CH₂ OC₂ H₄ OCH₂ and m is an integer of 1 to 4, or Y is a saturated or unsaturated alkylene group containing 1 to 4 carbon atoms which is optionally substituted by OH and R¹⁶, R¹⁷, R¹⁸ and R¹⁹ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ hydroxyalkyl groups, C₂₋₄ -(C₁₋₄ -alkoxy)-alkyl groups or groups NR²¹ R²² or OR²³, wherein R²¹, R²² and R²⁰ independently of one another represent hydrogen, C₁₋₄ groups, C₁₋₄ alkoxy groups, C₂₋₄ hydroxyalkyl groups or C₂₋₄ -alkoxy)-alkyl groups, with the proviso that at least one of the groups R¹⁶ and R¹⁷ and one of the groups R¹⁸ and R¹⁹ is a group NR²¹ R²² or OR²³, (d) an aminopyrimidine corresponding to formula (V): ##STR21## in which R²⁴, R²⁵, R²⁶, R²⁷, R²⁸ and R²⁹ independently of one another are hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups and Z is hydrogen, an OH group or an NR³⁰ R³¹ group, wherein R³⁰ and R³¹ independently of one another are hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups, (e) an indole derivative corresponding to formula (VIa): ##STR22## in which R³² is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³³ is hydrogen or a carboxyl group and R³⁴, R³⁵ and R³⁶ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups, and (f) an indoline derivative corresponding to formula (VIb): ##STR23## in which R³⁷ is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³⁸ is hydrogen or a carboxyl group and R³⁹, R⁴⁰ and R⁴¹ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups.
 14. A composition as in claim 13 wherein R¹ is an allyl group, a hydroxy group or a 2-sulfoethyl or 2-sulfopropyl group and R² to R⁵ are hydrogen.
 15. A composition as in claim 13 containing at least one amino acid or an oligopeptide containing 2 to 9 amino acids.
 16. A composition as in claim 13, wherein said amino acid or said oligopeptide is selected from the group consisting of arginine, cysteine, methionine, proline, tyrosine, valine, glycine, glutamic acid, histidine, aspartic acid, alanine, tryptophan, cystine, lysine, hydroxyproline, leucine, isoleucine, phenyl alanine, 3,4-dihydroxyphenyl alanine, serine, ornithine, threonine and glutathione.
 17. A composition as in claim 13 containing at least one aromatic amine corresponding to formula (III): ##STR24## in which R¹¹, R¹² and R¹³ are hydrogen, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, hydroxy groups, C₂₋₄ hydroxyalkyl groups, carboxyl groups, sulfo groups, C₁₋₄ aminoalkyl groups or NR¹⁴ R¹⁵ groups, wherein R¹⁴ and R¹⁵ independently of one another are hydrogen, C₁₋₄ alkyl groups, aryl groups or C₂₋₄ hydroxyalkyl groups; two of the groups R¹¹, R¹² and R¹³ together may form a fused benzene ring optionally substituted by a C₁₋₄, alkyl, hydroxy, carboxyl, sulfo, C₁₋₄ aminoalkyl or amino group.
 18. A composition as in claim 17 wherein said aromatic amine corresponding to formula (III) is selected from the group consisting of p-tolylenediamine, 4-aminophenol, 4-amino-2-aminomethylphenol, 3,4-diaminobenzoic acid, and 1-(β-hydroxyethyl)-2,5-diaminobenzene.
 19. A composition as in claim 13 containing at least one aromatic amine corresponding to formula (IV): ##STR25## in which Y is a direct bond or a group CO, SO, O, S, NR²⁰, wherein R²⁰ is hydrogen, C₁₋₄ alkyl or C₂₋₄ hydroxyalkyl, or O-(CH₂ -Z-CH₂ -O)_(m), wherein Z is a direct bond, a group CH₂, CHOH or CH₂ OC₂ H₄ OCH₂ and m is an integer of 1 to 4, or Y is a saturated or unsaturated alkylene group containing 1 to 4 carbon atoms which is optionally substituted by OH and R¹⁶, R¹⁷, R¹⁸ and R¹⁹ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ hydroxyalkyl groups, C₂₋₄ -(C₁₋₄ -alkoxy)-alkyl groups or groups NR²¹ R²² or OR²³, wherein R²¹, R²² and R²³ independently of one another represent hydrogen, C₁₋₄ alkyl groups, C₁₋₄ alkoxy groups, C₂₋₄ hydroxyalkyl groups or C₂₋₄ -(C₁₋₄ -alkoxy)-alkyl groups, with the proviso that at least one of the groups R¹⁶ and R¹⁷ and one of the groups R¹⁸ and R¹⁹ is a group NR²¹ R²² or OR²³.
 20. A composition as in claim 19 wherein said aromatic amine corresponding to formula (IV) is selected from 1,3-bis-(2,4-diaminophenoxy)-propane, 1,8-bis-(2,5-diaminophenoxy)-3,6-dioxaoctane and 4,4'-diaminodiphenylamine.
 21. A composition as in claim 13 containing at least one aminopyrimidine corresponding to formula (V): ##STR26## in which R²⁴, R²⁵, R²⁶, R²⁷, R²⁸ and R²⁹ independently of one another are hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups and Z is hydrogen, an OH group or an NR³⁰ R³¹ group, wherein R³⁰ and R³¹ independently of one another are hydrogen, C₁₋₄ alkyl groups or C₂₋₄ hydroxyalkyl groups.
 22. A composition as in claim 21 wherein the substituents R²⁴ to R²⁹ in formula (V)are hydrogens.
 23. A composition as in claim 13 containing at least one indole derivative corresponding to formula (VIa): ##STR27## in which R³² is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³³ is hydrogen or a carboxyl group and R³⁴, R³⁵ and R³⁶ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups, or at least one indoline derivative corresponding to formula (VIb): ##STR28## in which R³⁷ is hydrogen, a C₁₋₄ alkyl or C₂₋₄ acyl group, R³⁸ is hydrogen or a carboxyl group and R³⁹, R⁴⁰ and R⁴¹ are hydrogen, C₁₋₄ alkyl groups, C₂₋₄ acyloxy groups, hydroxy groups, amino groups or C₁₋₄ alkoxy groups.
 24. A composition as in claim 23 wherein said indole derivative corresponding to formula (VIa) or said indoline derivative corresponding to formula (VIb) is selected from the group consisting of 5,6-dihydroxyindole, 5,6-diacetoxyindole, 4-hydroxyindoline, 6-aminoindoline and 5,6-dihydroxyindoline.
 25. A composition as in claim 13 in the form of a powder containing at least one isatin derivative corresponding to formula (I) in a quantity of 1% to 90% by weight, and an amino acid or an oligopeptide containing 2 to 9 amino acids in a quantity of 1% to 90% by weight, based on the weight of said composition.
 26. A composition as in claim 25 wherein the isatin derivative corresponding to formula (I) is selected from N-allyl isatin, N-hydroxyisatin and N-(2-sulfoethyl)-isatin, and the amino acid or the oligopeptide is selected from arginine, cysteine, methionine, proline, tyrosine, valine, glycine, glutamic acid, histidine, aspartic acid, alanine, tryptophan, cystine, lysine, hydroxyproline, leucine, isoleucine, phenyl alanine, 3,4-dihydroxyphenyl alanine, serine, ornithine, threonine and glutathione. 